The role of lightness contrast in determining the magnitude of the Delboeuf illusion: A rejoinder to Weintraub and Cooper.

Sjostrom, Kristen P.; Pollack, Robert H.

doi:10.1037/h0032097

Cited by 7 publications

(8 citation statements)

References 9 publications

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“…Finally, the two-way interaction of 'The brief ex osure was used to diminish the influence of scanning, attention, and temporal integration on t i e illusion. See Sjostrom and Pollack 1972) for a more complete discussion of the methodology. Lightness x Circle Size was significant (F, ,, = 3.09, p = .O3, q i = .099).…”

Section: Resultsmentioning

confidence: 99%

Effects of Contour Proximity and Lightness on Delboeuf Illusions Created by Circumscribed Letters

Jaeger

Long

2007

Percept Mot Skills

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32 observers judged the size of a letter, either an "A" or an "S," which was surrounded by a circle. Both letters were overestimated, but larger surrounding circles reduced the illusion. Decreasing the lightness contrast of the surrounding circle relative to the central letter diminished the illusion. The results suggest that, like the Delboeuf illusion, these circumscribed letters illusions are produced by interactions among size-coding neurons.

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Section: Resultsmentioning

confidence: 99%

Effects of Contour Proximity and Lightness on Delboeuf Illusions Created by Circumscribed Letters

Jaeger

Long

2007

Percept Mot Skills

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“…Halfway between was a small (2 xz mm) plus sign for fixation. The cards were presented in a white holder, with the subject's head placed in a headrest to hold eye-to-display distance at 1.80 m. These dimensions kept the total display, comparison, test, and inducing portions, within a horizontal visual angle of 3 ", Pollack has argued that this visual angle ought to be no greater than 3 0 (Sjostrom & Pollack, 1972). A vertical slot in a white cardboard mask obscured all but the fixation mark.…”

Section: Methodsmentioning

confidence: 99%

Fragments of Delboeuf and Ebbinghaus illusions: Contour/context explorations of misjudged circle size

Weintraub

Schneck

1986

Perception & Psychophysics

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Variants ofthe Delboeuf (concentric circle) display and the Ebbinghaus display (four large nonconcentric inducing circles) were produced by systematically eliminating fractions of the circumferences of the outer inducing circles. For the Ebbinghaus display, various amounts of the inner arcs and/or outer arcs were preserved; a series of dots was sometimes substituted for missing contours. Results are described by the following statements: Contours attract. Larger nonconcentric circles induce size contrast. Rotating an Ebbinghaus variant by 45°alters size misjudgments. The larger the horizontal (or vertical) extent of the inducing configuration, the smaller the judged size of the test (center) circle. A figural aftereffect of the inducing configuration acts to reduce the perceptual size of the comparison circle when eye movements are permitted between test and comparison circles.The term illusion, because of its connotations of magic and deception, neither of which is germane to the topic at hand, shall be restricted to the title. Informativeness requires its inclusion in the title. At issue are explanations of the Delboeuf anomaly, size misjudgments of a circle in the presence of a concentric circle, and the related Ebbinghaus (Titchener circles) anomaly, which depends upon the presence of nearby nonconcentric circles. The underlying problem is to understand the processes underlying misperceived circle size. The present investigation relies upon displays that are sometimes only distant cousins to Delboeuf and Ebbinghaus figures.The research was designed to explore elements of a theory proposed on the basis of relatively modest evidence (Cooper & Weintraub, 1970;Weintraub & Cooper, 1972) but more recently buttressed by extensive evidence (Weintraub, 1979). In barest outline, the contour/circle-context model asserts that contours attract and that context supplied by the larger or smaller size of nearby nonconcentric circles leads to size contrast. Contour attraction, then, predicts that exterior contours produce overestimation of Experiment 2 was based on research by the second author for his senior honors thesis in the Psychology Department, University of Michigan.

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“…The Delboeuf illusion has been employed to alter the perceived size of a target. While the effect of lightness and contrast on the magnitude of the illusion has been considered in previous research (Oyama, 1962;Sjostrom & Pollack, 1972;Weintraub & Cooper, 1972), the reverse effect, i.e., the effect of perceived size on lightness, has received less attention. Brigner (1980), who examined the size and lightness interaction using a Delboeuf figure with grey disks, found that the grey disk that appeared smaller also looked "brighter."…”

mentioning

confidence: 99%

Illusory Lightness in the Delboeuf Figure

Zanuttini

Daneyko

2010

Percept Mot Skills

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A white disk presented inside a small concentric circle (a display like the Delboeuf figure) looks lighter than when inside a larger one. The magnitude of the effect was measured with 20 observers (10 women, 10 men; ages 19 to 26 years). The decrements in luminance of the disk inside the smaller circle, in order to match the lightness of the disk inside the larger circle, are reported for three different grey backgrounds and correspond to 9.13, 10.33, and 10.46%.

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The role of lightness contrast in determining the magnitude of the Delboeuf illusion: A rejoinder to Weintraub and Cooper.

Cited by 7 publications

References 9 publications

Effects of Contour Proximity and Lightness on Delboeuf Illusions Created by Circumscribed Letters

Effects of Contour Proximity and Lightness on Delboeuf Illusions Created by Circumscribed Letters

Fragments of Delboeuf and Ebbinghaus illusions: Contour/context explorations of misjudged circle size

Illusory Lightness in the Delboeuf Figure

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